CCTV images have been released of two men police want to trace in connection with the murder of a 24-year-old who had learning difficulties.

Dean Mayley was stabbed in the heart as he walked through Greenford, west London, on February 7.

He had a condition that meant he had a mental age of around nine.

Scotland Yard has released CCTV images of two men they want to speak to in connection with his death.

It had previously released stills from footage of Mr Mayley's final bus journey in an attempt to find his killers.

Two teenagers, both aged 17, have already been charged with murder. They are also charged with conspiracy to rob and possession of an offensive weapon.

A youth court remanded the pair in custody ahead of a bail hearing at the Old Bailey on Wednesday.

Detective Chief Inspector Matt Bonner, in charge of the investigation, said: "This was a vulnerable man who would have shown an unusual degree of trust in those who he came across and it is utterly sickening that he should have been set upon in this way."